Chapter 8, Problem 7E

Interpretation Introduction

Interpretation: The most likely hydride shift that will occur for each of the below carbocations should be depicted with curved arrow and reason behind lowered potential energy for thus newly formed carbocation should be explained.

  

Concept introduction: Carbocation is a general term employed for a postively charged carbon irrespective of valency of carbon. In carbocation, carbon is bonded to 3 atoms or groups and has only sextet of electrons so it behaves as an electron-deficient species. It is $s{p}^2$ hybridized with a vacant $p$ orbital and has a planar geometry.

The order of relative stability of various possible carbocation species is as follows:

  

Thus, whenever possibility to attain lower energy by rearrangement is there hydride or alkyl shift may occurs and results in more stable carbocation. This type of rearrangement is highly favorable in polar solvents.